Printing telegraph receiver



NOV. 19, 1935. T F LQUGH 2,021,366

PRINTING TELEGRAPH RECEIVER Filed .June 1'7, 1933 llllllllll INENTOR THOMAS E AOL/6H ATTORNE Patented Nov. 19, 1935 PATENT OFFIQE PRINTING TELEGRAPH RECEIVER Thomas F. Lough, Chicago, Ill., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Application June 17,1933, Serial No. 676,263

17 Claims.

The invention relates to printingtelegraph apparatus and more particularly to printing telegraph machines in which the characters are printed on a continuous length of tape.

The principal object of the invention is to provide a simple, inexpensive and efficient mechanism for positively shifting and unshifting the v platen, and during such operation preventing vibration thereof resulting from its stop impact.

In the following description, the invention will be illustrated with and described as applied to a printing telegraph unit similar to that disclosed in United States Patent No. 1,745,633 to S. Morton et al., February 4, 1930. In that disclosure, a shiftable platen is provided in association with a plurality of type bars that carry two sets of type characters. In accordance with each of its two positions, the shiftable platen is made to register in printing relation with one or the other of the two sets of characters. Each type bar, being provided with one character of each set, is accordingly effective in each position of the platen.

The shifting of the printing platen has, in some instances, been performed by a spring loaded element operative in one direction and a positive member operated in the other direction, and it was noted that with this method of operation slight or minor disturbances, such as the handling of the tape, have, during the spring shifting operation, materially interfered with and even prevented its proper response. To overcome these possible objections the present invention contemplates a mechanism for positively and mechanically shifting the printing platen into either of its positions, which assures the shift operations of the printing platen even under certain adverse operating conditions, and improves the general operation of the apparatus.

A better understanding of the present inventionmay be had by referring to the accompanying drawing and to the following description, in which one application thereof is particularly illustrated and fully described. In the accompanying drawing in which like reference characters designate similar parts throughout,

Fig. 1 is a plan view of a printing telegraph apparatus such as disclosed in the aforementioned patent, having applied thereto one form of the present invention;

Fig. 2 is a transverse sectional View taken approximately on line 2--2 of Fig. 1, and illustrating the present invention applied thereto, and

Fig. 3 is a detail sectional view of a portion of the mechanism illustrated in Fig. 2, showing other conditions of its operation.

For a complete understanding of the operation of the printing telegraph apparatus to which the present invention is applied, reference should be a had to the above mentioned patent, particular consideration being given here to that subject matter only which directly concerns or is affected by the operation of the present invention.

In the accompanying drawing, a plurality of selectable elements H are illustrated in an armate alignment. A set of code bar segments I2, supported near the upper portions of the elements H are capable, by being variously arranged, to offer a clearance to one of the elements H and thereby permit it to move rightwardly, as viewed in Fig. 2. In this position the lip portion l3 of any element H lies in the path of a periodically reciprocating bail I4 and is thrust upwardly to the position illustrated in dotted lines in Fig. 2.

Most of the elements ll relate to and, in being thus selected, perform a character printing operation, but certain ones thereof, having no printing levers or type bars l5 associated, per-,-

form other functions, two of which are concerned in the present invention and will be referred to hereinafter as the shift and unshift selectable elements or bars indicated by the reference characters l6 and I1.

Each of the printing levers i5 is provided with two type characters customarily classified as upper and lower case Ill and IS. A printing platen 2i, carried upon and secured to a shaft 22 is capable of limited longitudinal movement between the extremities illustrated in full and broken lines in Fig. 1. When in its left-hand position, platen 2| is referred to as being shifted and in this condition cooperates with the upper case type character is, while when in its righthand or solid line position, Fig. 2, it is referred to as unshifted and in this condition cooperates with the lower case type character I9 during the printing performace of any of the levers l5.

Two of the selectable elements l6 and I! are delegated to the performance of the shift operations, one each for the two positions as just described. When the platen is in its unshifted position, as illustrated in full'lines, Fig. 1, and, pursuant to a shift signal, is to be shifted to its other condition, the selectable element 16 is afforded a transverse clearance by the notches of segments 12 and is thereupon permitted to respond to the horizontal component urge of its operative cycle when bail l4 moves upwardly, the shoulder of bail 14- engages the lip I3 (not shown) of element 56, causing the latter to be moved upwardly against the vertical component of spring 23 and to engage through a hook 24 at its lower end, one arm 25 of a spider lever 26, rotating the latter in a counterclockwise direction about its pivot 2? and against the tendencies of a spring 28 connected to another arm 29 thereof. This last mentioned arm 29 is shouldered at 3! to engage a tooth 32 which is carried by a cradle 33 having a yoke 34 which straddles the platen 2i and its associated gear 35 through which the platen and shaft 22 are rotated. When lever 23 is thus rotated counterclockwise,

.tooth 32 is freed from engagement by shoulder 3| of lever arm 29, and the entire assembly, consisting of cradle 33, shaft 22, and platen 2!, is permitted to be moved leftwardly as resiliently urged by spring 48 and positively impelled by arm 4| and selectable element is. A third arm 4| of lever 26, moving leftwardly when the lever is rotated counterclockwise, engages the eccentric head of an adjustment screw 42, carried by an upwardly and rightwardly extending portion 43 of cradle 33, and moves the cradle into its shift position. The movement of the cradle is thus positively urged concurrently with the release of tooth 32 by shoulder 33. Thus, even if the yielding action of spring is interfered with the assembly will be shifted, nevertheless,

by the firm action of the lever through arm 4 i.

A rearmost bearing bracket 33 supports the rear end of shaft 22, while a foremost bracket 3? supports the front end, and has, in addition, a laterally extending arm 33 which carries an aligning pin 39 which passes through an opening of yoke 34 and assures thereby the parallel movement of shaft 22 and cradle 33 during the shifting of platen 2! in either direction.

It has been found that the shifting of the platen 2| in this manner, being necessarily an abrupt and sudden movement, is followed by a rebound or vibration when colliding with the stop screw 88. To prevent this rebound or vibration, an auxiliary lever 44, also pivoted at 2?, is provided, one end of which is shouldered as at 45 and is adapted to be presented into the path of a lug 46 which may be integrally formed with cradle 33. Lever 44 is urged into this position by spring 28, connecting it and arm 28 of lever 25 when the extension 4?, at its other end, is freed by the upward movement of hook 24 of bar 16,

which normally engages it and maintains it in the position illustrated in Fig. 2. In this manner, the two levers 44 and 25, acting conjointly, positively shift cradle 33 and platen 2| into the so-called shift position, while preventing the rebound or vibration which would otherwise result from an abrupt and sudden movement such as devices of this nature seem necessarily to .incur in keeping with telegraph transmission speed.

Lug 46 is blocked by the shoulder 45 of lever 44 for a short time only or as long as the shift bar l6 isin transit, for upon the return of bar it to its normal position, its hook 24 again engages the extension 41 of lever 44, withdrawing the shoulder 45 thereof from the path of lug 46, so

that upon a subsequent unshift operation, the cradle assembly may be unobstructed thereby.

The movement of the platen back to its unshift position is effected by mechanism which is reciprocally related to the shift mechanism just described and is fully explained in the patent referred to above. Its performance is initiated by the selection of bar or element H, which, like element i6, is moved upwardly pursuant to its selection, and in so doing, engages through a hook portion thereof one arm of a lever 48, the other arm of which is articulated to a bell crank 49, pivoted at 5!. The other arm of hell crank 49 is slotted as at 52 for receiving a depending portion of an appendage 53, integrally formed with one arm of the yoke 34 of cradle 33. The ascent of bar ll through its hooked lower portion rocks lever 48 which in turn rocks bell crank 49 clockwise, Fig. 2, pulling the platen assembly rightwardly against the tendencies of spring 40.

While this invention has been disclosed and described in connection with a particular adaptation, it will be understood that numerous modificat'ions and variations may be made without departing from the spirit or scope thereof. It is therefore intended not to be limited by any of .7;

ment and movable concurrently with it for pre-.

venting the rebound of said platen following the shifting thereof.

2. In a printing telegraph apparatus, a plurality of individually selectable elements for performing printing and conditioning functions, as.

rotatable platen longitudinally shiftable under the control of certain of said elements, a supporting carriage for said platen, and a lever operated by one of said elements having a portion for latching said carriage and a portion engaging said carriage during the unlatching by said first mentioned portion, for moving said carriage to its shift condition.

3. In a telegraph printing apparatus, a shiftable printing platen, a lever for shifting said platen, and a lever movable concurrently with said shifting lever for presenting itself aback said platen for preventing the impact rebound thereof.

4. In a telegraph printing apparatus, a plurality of operating elements, means for selecting and operating said elements under the control of telegraph signals, a printing platen, a platen shifting means, and a recoil preventing means, both of said two last mentioned means operative by one of said elements .and in response to one signal.

'5. In a telegraph printing apparatus, a selecting mechanism responsive to telegraph signals for individually conditioning a plurality of actuators, an actuator under control of said mechanism, a shiftable printing platen, a shifting lever responsive to the movement of said actuator in one direction for shifting said platen, and a blocking lever responsive to the movement of said actuator in the same direction as aforesaid for preventing the impact rebound of said platen when shifted and to the movement of said actuator in the other direction for withdrawing from blocking position.

6. In a telegraph printing device, a set of typelevers each bearing two type characters, a printing platen shiftable for accordingly accommodating each of said characters, a spring normally urging said platen into shift position, a latch normally restraining said platen in unshift position, a signal responsive selectable lever for releasing said latch, and a blocking member operable with said lever for preventing the impact rebound of said platen when shifted by said spring.

'7. In a printing telegraph machine, a shiftable platen, a spring for assisting the movement of said platen into its shifted position, a lever having a latch portion for restraining the movement of said platen in its shifted position, and another portion movable during the release movement of said latch portion for camrning said carriage toward its shifted position.

8. In a printing telegraph machine, a shiftable platen, a signal responsive element selectively movable for shifting said platen including a lever having a catch for restraining said platen, an arm movable during the release movement of said catch for urging said platen into its shift position, and an arm engageable by said element during the latters selective movement, and a lever engageable by said element during the latters return movement from selection for preventing rebound from its stop impact.

9. In a telegraph printing apparatus, a longitudinally shiftable printing platen, a lever for moving said platen into one of its shift positions, and a blocking member rotatable independently of but movable concurrently with said shifting lever for preventing the rebound impact of said platen tending to result from the movement thereof by said shifting lever.

10. In a telegraph printing apparatus, a shiftable printing platen, a signal responsive selectable element, means under the control of said element for moving said platen into one of its shift positions, and independent means also under the control of said element for preventing any impact rebound tendencies of said platen resulting from said moving means.

11. In a telegraph printing apparatus, a shiftable platen, means under the control of certain selecting signals for shifting said platen, and means also under the control of said signals and effective momentarily during the conclusion of said shift operation for preventing the rebound tendencies thereof.

12. In a printing telegraph apparatus, a-shiftable platen, means responsive to certain signals for shifting said platen including a selectively conditioned element, a lever receiving motion from said element to be transmitted to said shiftable platen, and a member normally held in disengagement by said element but momentarily released into engagement during the selective operation of said element to prevent the impact rebound tendencies of shifting said platen.

13. In a printing telegraph apparatus, a shiftable platen, a lever for shifting said platen, blocking means for preventing the impact rebound tendencies of shifting said platen, and a member normally maintained in ineffective position and conditioned for operation in response to a predetermined signal including a portion engageable with said shifting lever during the selective conditioning of said member and engageable with said blocking element during the normal condition of said member.

14. In a printing telegraph apparatus, a shiftable platen, means responsive to telegraph signals for shifting said platen from one of its positions to another in one direction, and a blocking member movable transversely to said direction to be presented aback said platen for preventing the impact rebound tendencies thereof.

15. In a printing telegraph apparatus, a shift- .able platen, means for shifting said platen, a blocking member for preventing the impact rebound tendencies of shifting said platen, and an element automatically conditioned and operated in response to predetermined telegraph signals including a portion for engaging and operating said shifting means during the operative movement of said element, and a portion for retracting said blocking means upon the return movement of said element.

16. In a printing telegraph apparatus, a shiftable printing platen, an element automatically responsive to control signals for shifting said platen, and means for translating the selective movement of said element into shift movement of said platen including a lever having a portion for engaging .and moving said platen into shift position, a portion for engaging and holding said platen in unshift position, .and a portion engageable by said selectable element. 17. In a telegraph printing apparatus, .a shiftable printing platen, a lever for moving said platen into one of its shift positions, a member for blocking said platen for preventing the impact rebound incident to its shift operation, and means for first conditioning said member to seek its effective position and for thereafter initiating the performance of said shifting lever.

THOMAS F. LOUGH. 

